Part of the beauty of this game is its sense of ‘80s games. Not only is is presented with the appropriate graphics of the era but it also has many of the same features: inescapable intros, quick and overly useful cheats (that involve combinations of up, down, B and A), tinny music and even a nod to questionably sequel-ized franchises.
The developers did well in creating games that could have easily been released in the mi-‘80s. Each of the two space shooters represent the two ends of the genre (fairly simple and seemingly impossible). The Haggle Man series of games represents not only the milking of a franchise but also how the same game can evolve into something completely different, in this case, from a low graphics, single-room platformer to a multi-level, backtracking Castlevania clone (those who believe this is a Ninja Gaiden clone need to go back and replay the original Castlevania - some of the room elements are identical to the point that I even knew where I could break through a wall without thinking).
To help mix things up a bit, the challenges in the game are not all your standard “make it to level X” or “score X points” - though there are a few of those - but often involve a very specific task that may not even require that you finish a level. Some examples, which often require that you read the in-game fan magazines (and you are heavily guided in that respect), include warping twice in Cosmic Gate, clear the third level of Haggle Man (1) without using ninja stars, get a 1UP in Star Prince and, the shortest challenge, get a starting line boost at the beginning of Rally Race 2.