As a former House of the Dead obsessive I quite enjoyed my time with this game. I like the fact that it supports two players simultaneously. In an arcade this would work well with either light guns or two trackballs and a fire button and reload button each.
I also like the looping aspect of it, and how the speed seemingly increases with each loop to increase the challenge, along with enemy placement randomisation to ensure no two loops are the same. In essence, because there was no win condition I could see it is a survival/score attack game (last as long as possible and score as high as possible), and we definitely saw that a lot in classic arcade titles.
I'm in two minds that (like the original House of the Dead) the reload is instant, which can be abused by the players (at least those using mice or trackballs rather than light guns), or one could argue that it is part of the skill gap as knowing to use it, as it is part of the game mechanics.
But yeah, this was a solid entry.