It's a simple game, but it feels like it was a little rushed.
Graphics are quite simple, even considering the screen resolution. That doesn't affect gameplay itself that much, but the title screen, unfortunately, just doesn't leave a good first impression in terms of authenticity. I assume you were using Construct, right? I think the text would've been a lot better if you had used Sprite Fonts. Given the limitations, I think small fonts, like PICO-8 font, would be a nice fit here.
There's no soundtrack, just sound effects. Noisy, highly-pitched sound effects! I recommend to mute the tab if you want to try seeking for higher scores. Otherwise, it's kinda annoying to hear that everytime you get a new record.
Gameplay seemed hard to me at first, mostly because I assumed it would play just like any typical platformer, where you just move left/right and jump. Then, after getting my first "double spike" stairs, I ended up getting a little bit frustrated at that point...
...until I found that you can double jump! Doing so also shoots a laser down, making it possible to destroy spikes. After that, I found the game quite fun to play for a while! After 50 or 60 points, a monster will spawn. It will push the stairs and make it harder for you to climb up.
I think the game could be a lot better if it had just a little bit more of polishment, like fixing the title screen, giving a few improvements to graphics, etc. The game may look confusing at first, but becomes fun after you learn to double jump over spikes. That's what made me enjoy it!