Fortran is mainly a mathematical programming language that facilitates programming mathematical applications. It is simply not suitable for game programming (although it can be done; I've seen OpenGL programs written in Fortran). But Fortran is not made for this, and ClassPad is not a game platform as well. What I said about the "rotten C++" was obviously a joke, as an answer to Kilburn's joke.
The CPLua interpreter is fast enough to write games, but, if the game is complex, the interpreter shows its limitations, concerning speed. It is, however, much faster than CP Basic. If you are not using the SDK, CPLua is currently the best way to write a game for ClassPad, for whoever is interested to do so.
I know Fortran is a mathematical language, my remark was obviously a joke as well

I'm sure the Lua interpreter is more than fast enough to execute most game logic. For most games, all that's needed would be a fast sprite library that can be accesses from Lua, with drawing, loading, moving, colission detection, etc.
Every language, or every language paradigm, has its place, and mathematical programs aren't the only "serious" programs

While Fortran makes it easier to write the mathematical logic, it doesn't make any difference to the final user of the application which language it's been written in. On a platform like the classpad, I don't think you can rely on a language like Fortran (or Lua) for really heavy operations... you need to go lower level to squeeze more performance out of the limited hardware.