श्रीभगवान्
In plain words
The Blessed Lord said: This form of Mine that you have seen is exceedingly difficult to behold. Even the gods are ever longing to see this form.
Word for word
This form of Mine which you have seen is very hard to see; even the gods are always longing for the sight of this form.
सुदुर्दर्शमिदं रूपं दृष्टवानसि यन्ममदेवा अप्यस्य रूपस्य नित्यं दर्शनकाङ्क्षिणः
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam· bhāṣya
सुदुर्दर्शं सुष्ठु दुःखेन दर्शनम् अस्य इति सुदुर्दर्शम् , इदं रूपं दृष्टवान् असि यत् मम, देवादयः अपि अस्य मम रूपस्य नित्यं सर्वदा दर्शनकाङ्क्षिणः ; दर्शनेप्सवोऽपि न त्वमिव दृष्टवन्तः, न द्रक्ष्यन्ति च इति अभिप्रायः ॥ ५२ ॥
In plain words
Sudurdarśam — 'very hard to see': su means to an extreme degree, dur means only through great hardship, and darśana is the seeing. So: a form whose sight is won only with the utmost difficulty. This form of mine, which you have just seen — even the gods and the beings above them go on longing for it, constantly, without a pause. And for all that longing, they have not seen it as you have seen it, and they will not. That is what the Lord means.
Close to the Sanskrit
Sudurdarśam: the seeing of this is possible only with very great difficulty — thus, 'very hard to see'. This form of mine which you have seen: even the gods and the rest are always, at all times, longing for the sight of this form of mine; though they wish to obtain that sight, they have not seen it as you have, and they will not see it — this is the purport.