Obviously not the kind of game that revolutionises the gradius series like Gaiden or V but ReBirth is a good reimagining of Gradius I in its own right. Some parts feel rough but the stages are fun with visually striking boss fights.
It also has the same weird difficulty curve that Gradius I has where some sections are actually easier to do on recovery pace than fully powered up because the rank gets pretty crazy.
It also has the same weird difficulty curve that Gradius I has where some sections are actually easier to do on recovery pace than fully powered up because the rank gets pretty crazy.