It's so bad.
Shooting while jumping kills all momentum from the jump.
Recoil when taking damage is very high, making it easy to fall off platforms.
When walking, scrolling is very jerky. When jumping, scrolling is very smooth.
Vertical area takes up more than one screen length so you have to make blind jumps.
Looking it up, It's not even the same dev as the previous Zook Hero games (they're not great but still better than this). Sintax took the name and some assets from Vast Frame, so this is a bootleg of a bootleg.