Gizmo is a Support Character that focuses on set-ups, supporting your ally, and has very strong aerial attacks. Due to his size, it can be hard for the enemy to hit you, and you have multiple tools to deal with projectile characters. His aerial moves are very good, and can usually combo off your Arrow quite well. Since some of your moves last deceptively long, you can catch people who dodge frequently with moves like your Up Special or Aerial Side Special.
In Teams or 2v2, you can help your ally start combos with your tools, or get the enemy off of them with various attacks. He performs very well in Teams, due to his size and how big some of the hitboxes on his moves are. However, your disadvantage state can be hard to get out of if you don't have any Arrows left, and some of his recovery options are predictable and can be countered easily, leaving it up to you to mix up your recovery in certain ways to gain the advantage.
Gizmo Match-up Chart
Gizmo is very good at combo-ing off of his main projectile, his Bow and Arrow (Neutral Attack). This is one of your main engage tools when approaching enemies. It can also be used quite quickly after some attacks, such as your Umbrella (Aerial Side Special). When fully charged, the arrow does 10 damage max, so try to use it during combos to extend them further.
Gizmo should win matches against Iron Giant due to the size of Gizmo, his aerials, and the effectiveness of his kill options due to Iron Giant's size. Things like your Car (Grounded Side Special), Umbrella (Aerial Side Special), Leap (Up Special), and Aerial Down Special are all more effective against Iron Giant, allowing easier combo potentials and follow up attacks. For Arya and Batman, your arrows can destroy Batarang or Arya's dagger quite easily if you can react fast enough, and using your Bow can stop them from approaching too easily. Arya and Batman are also lighter characters, which makes it easier for your to kill. You can also approach with your Umbrella, as it blocks projectiles, and the hitbox for it lingers longer than most people expect. Especially since Batman likes to go in after throwing Batarang, it can unexpectedly hit them. It also is a decent kill move closer to the sides of the stage. Arya can be tricky to deal with, but your moves with long active hitboxes do well against her.
Gizmo can struggle getting out of disadvantage, especially against characters that can edge guard well, or can string hits together very fast. Characters like Wonder Woman can invalidate some of your approach tools if you aren't playing around her armor, or Morty can be extremely difficult to hit if you can't engage with your Bow. Without hitting arrows, a lot of your moves are more committal, which these characters can quickly punish you for not being able to act immediately from some of your options. You must look for windows to start your combos to gain the advantage. Using popcorn (Ground Up Attack) can help gain stage control, letting you punish them if they get too close, but can take practice to get the popcorn to properly go where you want. Hitting the popcorn with an arrow shot creates a cone explosion the direction the arrow traveled, and this explosion is bigger if your arrow is on fire\fully charged. Stripe is very hard to approach as Gizmo, he is harder to hit, has bigger hitboxes than yours, and when trying to recover, you don't have many options to get back on stage, which is one of Gizmo's bigger flaws in my opinion. Stripe's Sawblades can invalidate your Car, his chainsaw move is especially hard to counter, as Arrow's will sometimes go through him and won't interrupt. The best way to play this match-up is to try to keep your distance, poking him with your tools, and starting combo chains when you hit arrows. Try to approach with the bow, or throw some popcorn out and make him weary of that. When recovering against him, Stripe will usually use his gun after knocking you off-stage, so try not to use specials or dodges right away unless absolutely necessary, as it is quite easy for him to interrupt them. If you can, wait to use moves so you don't lose air options.
Best Perks For Gizmo
For Attack Perks, these perks all improve Gizmo's main projectile, his Bow and Arrow, in some way. Ice to Beat You! can make follow-ups easier with the decrease in movement speed, That's Flammable, Doc! increases the amount of damage you can deal with the projectile, and Make It Rein, Dog! helps the arrow reach the enemy faster.
For Defense Perks, Boundless Energy and Slippery Customer improve your dodge distance and recharge rate of the dodge meter. Being able to get out of disadvantage easier helps Gizmo a lot, so making your dodge better lets you get out of bad situations easier. Toon Elasticity can helps against characters like Stripe, Reindog, Morty, and anyone with good stage spike tools.
For Utility Perks, Triple Jump is excellent for chasing people and trying to kill earlier with either Up Special or Aerial Up Attack. Since these can both kill pretty reliably, being able to chase enemies into the air, closer to the ceiling blastzone can lead to some earlier ringouts. Tasmanian Trigonometry is always nice, and can help getting out of disadvantage. Finally, Speed Force Assist just helps you become faster, which is always a plus. This could be traded out for something like Leg Day Champ, or Aerial Acrobat, and it would still be pretty beneficial.
For Signature Perks, overall I feel that Bounce, Bounce, Boom! is his best one for 1v1's at least. It can allow some unique set-ups, allowing more interactions and options for some of your kit. In 2v2, you could run Power Cuddle if you wanted too, but attaching to allies limits your options, which leads me to believe that Bounce, Bounce, Boom! is better. When attached, you can use your bow, keyboard (Down Attack), throw out popcorn, or you can leap off of your ally with your car. In my opinion, attaching to allies doesn't really give much benefits using Power Cuddle doesn't give many benefits. I also think that Bounce, Bounce, Boom is pretty situational, and Rhythm's Gonna Getcha is extremely hard to get to work. All of Gizmo's signature perks don't impact his gameplay too much, but Bounce, Bounce, Boom! allows for more interactions with your tools, allowing more options and set-up potential.
Placement in the Tier List
Gizmo is pretty good in 2v2, but can struggle in 1v1 when against certain characters. With a good teammate in 2v2, he can more easily set-up kills and confirm them with his moves that are slower. It's also very easy for him to get his ally out of combos. He also brings things like his attach mechanic to the table, helps his add damage to his teammates combos, however it can be tricky to learn when or when not to use it. The silence buff is also easier to get in 2v2, which is hard to get off but helps. Gizmo is better in 2v2 than 1v1 in my opinion, but can still get results in 1v1. Note, this tier list is not ranked in the tier itself.