CRPG Dev has recently been giving Turbo Rascal Syntax Error (TRSE) a try with positive results. TRSE is an IDE tailored to fit 8-bit/16-bit coding at its best, and it was born out of the need for C64 coding support. Over time however, it has evolved to encompass not only the Commodore 64 but also Commodore Amiga, MS-DOS, and ZX Spectrum platforms. TRSE uses a Pascal-style language which CRPG Dev had prior experience with due to his University studies. All in all, it is an ideal environment to code classic retro games easily and efficiently.
This development suite consists of robust features for seamless coding, such as inline assembly language support for higher speeds, abundant example code, a profiler to show data-heavy routines, and editors for graphics and maps. It makes doing special tasks straightforward with SID file support specifically crafted for C64 users, raster interrupts for split-screen effects or sprite multiplexing, and plenty more functions waiting to be explored.
The transition to CC65 (which is based on the C programming language) can prove challenging since earlier code might not work as expected when rewritten in Pascal; fortunately, the included set of examples was useful in quickly grasping the key concepts and making corresponding changes. Optimizations and assembly language remain open possibilities if needed.