Classic memorizer, but the issue is just that the hitboxes are just terrible. Your ship sometimes can go over halfway into a wall, on other walls, you die before you even touch the wall at all. Your forcepod protects you from bullets that don't even look like they would be blocked, but then other times a bullet will just somehow slip by and hit you. Sometimes bullets literally go straight through walls. Enemies will sometimes die when they attack you from behind, but other times they just don't and kill you instead. Your bullets will oftentimes just go straight through enemies (especially larger ones) without damaging them, or the time to kill on an enemy will be very inconsistent just because they have some minuscule hitbox or something. It really just feels awful to have a game demanding such precision to have such wildly inconsistent and nonsensical hitboxes all throughout the game.

A good memorizer should ideally have some degree of execution, a bit of variance/RNG, should feel very tight and deliberate in its gameplay and mechanics, and you should also feel like you're refining your route every time you play. R-Type really just doesn't really have those. It just feels frustrating due to lousy mechanics, extremely poor hitboxes, and excessive slowdown. The bosses are a complete pushover and trivialized entirely by safespots, the gimmick is not all that interesting as it's a bit clumsy and you rarely want to be separated from your pod as the protection benefits are just too great, and the enemy formation spawns and movements just feel cheap.