A bit of history about Princed, from poirot (dated 20 May 2013):
PV1 was made in pascal, I used it not to edit production levels but to understand the format. Once I unveiled something I coded a features in PV1 to support it. At the end of the development PV1 supported even screen linking. Gate system was developed later. The whole program, as you have seen was in full DOS interface. PV2 was made in pascal based on bill kirby wolf 3d mapedit. Improved graphics, intended to be used on production.
During this phase I developed the gate system and other stuff.
When the format knowledge was mature I started PV3, I was thinking in the Windows platform to reach more users, by the time I'd evaluated doing it in web, but canvas wasn't developed by that time; I've also evaluated GTK, but finally I decided to do it in windows with a portable C++ class to support all the levels. I installed windows and started coding it, but my knowledge of MFC was very limitated, so Youngmook Kim (moogi), an expert in the field joined the team. We created 6 alphas but one day he desappeared with all the sources of PV3 alpha 6 (I think). He claimed to have lost his notebook in Seoul subway. Alpha 5 source survived along with my level editing C++ classes, which I improved and now they support POP2.
By that time I've met Brendon, so I decided to stop the project and let Brendon continue with Roomshaker (I understand PV3 was intended to be 100% user friendly and format-transparent to the user, I even had plans to use future cuspop-like development to overcome some format limitations. That is why PV3 was wysiwyg, a complete new concept against PV1 and 2. RS was still using PV2 concept of one room editing at the time and using some gate system options which are very similar to the format (trigger next gate). PV3 gate system was conceived to support a list of gates activated by the same trigger, since the libraries itself, hiding the "trigger next gate bit" to the final user. A compressor was coded to support more than 256 gates reusing lists that were incloded on others.
Guard clothes were also able to be edited because we knew the guard palette offsets. With the development of PG (then PR) we discovered how to create up to 255 different guard types/clothes.