According to its official website, Dinoforce appeared in various issues of PC Engine Gekken around 1991, before vanishing completely. A ROM was never made publicly available and for decades no one really had any idea about how complete it was before it was canned.
However, now thanks to the original designer Tokuhisa Tajima (Kageki, Heavy Engine) who kept the ROM, the French collector Alex Seimando, and a group of developers and artists at PCEWorks that provided some fixes and rebalancing, it's possible to experience this curiosity from Uni Post for yourself. Better late than never, we say!
Dinoforce is a horizontal shmup that has you blasting away enemies, obstacles, and bosses to reach the end of each of its various stages. To start, you only have two weapons at your disposal. One is a primary laser and the other is an additional proximity attack that is activated whenever you choose to stop firing. You'll find additional weapons and powerups as you go, as well as encounter other secrets like hidden bosses and enemy alarms that fill the screen with baddies.
If you want to try out the game for yourself, there are a few options available to you. You can download the ROM now and play it on an emulator for free or you can splash out for a physical copy. The most basic options will cost you €89, and come in three variants: a Turbografx-16 US edition, a PC Engine Version Blue edition, and a PC Engine Version Amber edition. They're available now for pre-order from the official website and are expected to ship before the year's end.