I think its cool that Speccy has a leveling system, but it feels very underwhelming. HP and Speed, that's it? I would have expected them to gain more base moves, or enhancements to their existing abilities. Right now, they're an Amy that replaced the spread shot of her hearts from the hammer for a double jump.
I was thinking on leveling, they'd get things like moves that use Crouch + Jump/Spin for more moves. Like, pressing Crouch+Spin for a quick burst of speed from a standstill, or Crouch+Jump for a super jump. Maybe give them the ability to do a third jump or launch a spread of projectiles ala Amy when you level up enough. There's potential for much more, and none of it is being used right now. Leveling up just ain't exciting.
So if Speccy's core gimmick doesn't mean much, there's little reason to play as them. Their current abilities are nothing special, their appearance isn't much to write about either, and they just got no other legs to stand on.
Speccy's leveling system is the best they've got, so you need to push it! I got no clue what happens when he's at level 200 (way too much grinding needed to get that far, even getting to level 50 took too long hitting Destroy All Robots to do), but you should really put some new/enhanced moves every few levels to make leveling up something with anticipation and payoff!