Blockland uses a custom installer and seems to install itself into Program Files (as it was probably created in the days when 64bit was rare), whereas a newer installer (or maybe an .msi) would install into Program Files (x86) because that's where 32bit applications on 64bit systems seem to belong.
Correct, except for the Blockland installer part.
Blockland installer is built using NSIS (Nullsoft Scriptable Installer System). On Windows Vista and newer it's defaulting to C:\Blockland (provided your system drive is called C) because of UAC (user account control).
So, the only case where it would default to Program Files (x86) would be either if you ran Windows XP Professional x64 (which is quite uncommon and I don't know if it had the PFx86 folder) or if you turned of UAC (which I'm not sure would trigger it to default to PFx86).
X86 is 32Bit Apps The Normal one is for 64Bit Apps
That is for all 64Bit Windows Systems
The separation is good for two things.
- It keeps the user informed of which applications are ran through WoW64 (Windows 32-bit on Windows 64-bit) (the wrapper which lets you run 32-bit applications under 64-bit)
- Since 64-bit applications can't use 32-bit libraries and vice versa, this creates different "namespaces" where the applications can load libraries, and some applications might even install twice, to allow for 32-bit plugins