Wave 90 on Tier 1, nice! Glad the fix did the trick. Hope you have fun with the higher tiers!
And if you're enjoying it, a rating would mean a lot. It's a tiny solo project and every rating helps it get seen!
Good catch, thanks for reporting it! At 2x/3x (and especially on slower devices) shots were taking big jumps each frame, so they could skip right past enemies hugging the tower and bounce back and forth instead of hitting.
Fixed: the game now simulates several small steps at higher speeds, so shots behave exactly like at 1x. The update is already live. How far did you get?